Year,Spring_kg_tow,Fall_kg_tow
1963, ,3.4600
1964, ,1.9980
1965, ,2.2740
1966, ,4.5600
1967,,2.0240
1968,3.3530,3.4860
1969,2.5300,4.4000
1970,4.4860,3.7110
1971,2.0400,2.9520
1972,4.0050,2.4180
1973,6.2120,2.0540
1974,3.6220,1.5820
1975,2.7480,1.0300
1976,3.7010,0.9360
1977,1.9620,3.3830
1978,2.5620,2.9370
1979,1.7070,1.6230
1980,3.8940,2.0360
1981,4.0490,2.1930
1982,1.8670,0.8340
1983,2.7380,2.1160
1984,1.6630,2.3350
1985,2.7520,1.5930
1986,1.3480,1.0860
1987,0.6510,0.3730
1988,0.8460,0.5700
1989,0.7440,0.3750
1990,0.2360,0.4000
1991,0.5740,0.5360
1992,0.4820,0.2380
1993,0.3600,0.5390
1994,0.5310,0.4210
1995,0.4670,0.6240
1996,0.2770,1.0200
1997,0.4330,0.7680
1998,0.7650,0.4700
1999,0.4820,0.8780
2000,0.5190,1.1100
2001,0.7540,1.7110
2002,1.6150,1.0630
2003,1.2989,0.7920
2004,1.0812,1.0322
2005,0.8870,0.3810